Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
The most commonly used method for disinfecting such large spaces and surfaces involves the use of gases such as ozone or chlorine dioxide which are oxidative or corrosive and toxic, or may involve gases such as ethylene oxide or aldehydes, such as glutaraldehyde or formaldehyde, which are extremely toxic and which leave potentially harmful residues on surfaces. Steam is sometimes used and is hazardous to the operator because of the high temperatures involved and leaves a dense moisture on the surface which may lead to rusting.
From a health and environmental perspective it would be preferable to use hydrogen peroxide or peracetic acid as a disinfectant. Hitherto, as discussed in Ronlan U.S. Pat. No. 6,500,465, high density fine aerosols (aerosol droplet diameter less than 50 microns) of peracetic acid or hydrogen peroxide suitable for disinfecting have only been considered stable at 100% relative humidity.
Also hitherto, aerosols have suffered from the general problems that they were not effective at penetrating covered surfaces. This meant that door locks, hinges and the like as well as occluded surfaces such as, for example, an area of floor beneath a chair, could harbour organisms.
Another problem is that aerosol particles tend to settle and wet out the surfaces on which they fall, leaving an undesirable residue on the surface which must be cleaned off. In our co-pending Australian Patent Applications 2005904196, filed Aug. 4, 2005, entitled, “Improved Aerosol” and 2006900748, filed Feb. 15, 2006, entitled, “Membrane Sterilization” the content of which is incorporated by reference, sterilising or disinfecting agents are disclosed which can be adapted for treating large surfaces or spaces.